1. Field of the Invention
This invention relates to a lubricant concentrate and to an aqueous lubricant solution based on fatty amines and optionally typical diluents and/or auxiliaries and additives which contain at least one polyamine derivative of a fatty amine and/or a salt of such an amine.
The invention also relates to a process for the production of the lubricant concentrate and to the use of the lubricant concentrate and the aqueous lubricant solution as chain lubricants in the food industry. More particularly, the lubricant concentrate according to the invention is used for lubricating, cleaning and disinfecting automatic chain and belt conveyor systems which are used for the filling of foods, preferably beverages, into glass and plastic bottles, cans, glasses, casks, beverage containers (KEGS), paper and cardboard containers and the like.
2. Statement of Related Art
In bottle cellars and barrel cellars of beverage factories and in the packaging of foods, the corresponding containers are normally transported on plate-type conveyor belts or other conveyor systems which are lubricated and kept clean with suitable aqueous lubricant preparations via immersion-type lubrication systems or, recently, even via automatic belt lubrication systems.
Whereas immersion-type lubrication systems present hardly any problems in regard to their performance properties and the choice of the lubricant, precipitations of poorly soluble salts and microbiological deposits in the nozzles and filters of the central lubrication systems can seriously disrupt the continuous packaging of foods, particularly beverages, so that the systems always have to be switched off and cleaned after a certain period of operation.
The chain lubricants hitherto used as lubricants are based on the one hand on fatty acids in the form of their water-soluble alkali metal or alkanolamine salts or on fatty amines in the form of their organic or inorganic salts.
Whereas both classes of compounds can be used without difficulty in immersion lubrication, they show a number of disadvantages in the central chain lubrication systems typically used today. Thus, DE-A-23 13 330 describes soap-based lubricants containing aqueous mixtures of C.sub.16-18 fatty acid salts and surfactants. These soap-based lubricants have the following disadvantages:
1. They react with the hardness of the water, i.e. with alkaline earth metal ions, and other ingredients of the water to form poorly soluble metal soaps, so-called primary alkaline earth metal soaps. PA1 2. The soap-based lubricants react with carbon dioxide dissolved in water or in the product to be packed. PA1 3. The in-use solution thus produced is always germ-promoting. PA1 4. Where hard water is used, ion exchangers have to be used for softening, which represents an additional germ source, or products of high complexing agent content have to be used which is ecologically unsafe. PA1 5. Increased foaming occurs which, in particular, gives rise to problems for the bottle inspector (automatic bottle control) and to possible penetration of the lubricant into the transport container. PA1 6. Most of these products contain solvents. PA1 7. The cleaning effect of the products is poor so that separate discontinuous cleaning is always necessary. PA1 8. The soap-based lubricant preparations in question show pH-dependent performance behavior. PA1 9. In addition, soap-based lubricant preparations are dependent on water temperature. PA1 10. Soap-based lubricants show poor stability in storage, particularly at low temperatures. PA1 11. The EDTA (ethylenediamine tetraacetate) present in many products shows poor biodegradability. PA1 12. The soap-based lubricant preparations in question are not suitable for all types of plastic containers because stress cracking often occurs in the containers where these preparations are used. PA1 R.sup.2 is hydrogen, a C.sub.1-4 alkyl or hydroxyalkyl group or --A--NH.sub.2, PA1 A is a linear or branched C.sub.1-6 alkylene group and PA1 A.sup.1 is a linear or branched C.sub.2-4 alkylene group,
Apart from these so-based lubricants, lubricants based on fatty amines are otherwise mainly used. Thus, DE-A-36 31 953 describes a process for the lubrication of chain-like bottle conveyors in bottling plants, particularly in breweries, and for cleaning the belts with a liquid cleaning preparation which is characterized in that the chain-like bottle conveyors are lubricated with belt lubricants based on neutralized primary fatty amines which preferably contain 12 to 18 carbon atoms and which have an unsaturated component of more than 10%.
EP-A-0 372 628 describes fatty amine derivatives corresponding to the following formulae: ##STR1## in which R.sup.1 is a saturated or unsaturated, linear or branched C.sub.8-22 alkyl group,
as lubricants.
In addition, lubricants based on N-alkylated fatty amine derivatives containing at least one secondary and/or tertiary amine are known from DE-A-39 05 548.
The main disadvantage of these lubricants is that they react with anions in the water, more particularly with sulfates, bicarbonates, phosphates and carbonates from alkaline waters, and other water ingredients.
In addition, these lubricants based on fatty amines show unsatisfactory foaming behavior. Thus, the lubricants according to EP-A-0 372 628 tend to foam vigorously so that the material transported on the belt has to be subsequently cleaned. By contrast, the lubricants according to DE-A-39 05 548 show inadequate foaming so that the lubricant film applied soon drains off.
Accordingly, the main disadvantages of the lubricants mentioned above are the pronounced dependence on water of soap-based lubricants and, on the other hand, the compulsory cleaning of the system at regular intervals where lubricants based on fatty amines are used which is again attributable to the water ingredients. The precipitations occurring in both known processes have to be removed at the same time. A simple acid/base reaction is used for this purpose. In the case of soap products based on fatty acids, alkaline cleaners containing complexing agents are used to this end, cleaners in the form of organic or inorganic acids being used as technical equivalents in the case of products based on fatty amines.
Finally, there are some known chain lubricants which only have some of the disadvantages described above. Thus, EP-A-0 044 458 relates to lubricant preparations which are substantially free from fatty acid soaps and which, in addition, contain a carboxylated nonionic surfactant and an acyl sarcosinate. The pH value of these products is in the range from 7 to 11 and is thus preferably in the neutral to alkaline range.
Finally, DE-A-38 31 448 relates to aqueous soap-free lubricant preparations which form clear solutions in water, to a process for their production and to their use in particular as lubricants for plate-type conveyor belts used for transporting glass bottles or polyethylene terephthalate bottles. The substantially neutral aqueous lubricant preparations (pH 6 to 8) contain alkylbenzene sulfonates, alkyloxyated alkanol phosphates and alkane carboxylic acids, optionally in addition to typical solubilizers, solvents, defoaming agents and disinfectants.